Cellular telecommunications networks include a core network for switching purposes and a so-called Radio Access Network (RAN) including a multitude of cells providing service to mobile stations. RANs are divided into registration areas which typically include from several to sometimes hundreds of contiguous cells. Cellular telecommunications networks are designed with overlapping contiguous cells to enable smooth handovers of mobile stations between adjacent cells as mobile stations change their geographical location. Cells include a Cell Configuration Register (CCR) for storing cell configuration information, for example, cell identity, its registration area, broadcasting strength, etc.
Mobile stations have two operative states as follows:
First, a so-called default passive or idle state in which the mobile stations are in reception mode only. Passive mobile stations are located in a so-called camping cell. Passive mobile stations do not send measurements reports to the radio access network to save battery consumption and network resources.
And second, a so-called active state in which the mobile stations are in a bi-directional communication session with their host network. Active mobile stations are located in at least one so-called serving cell. Serving cells can change during a bi-directional communication session but an active mobile station's initial serving cell is the last camping cell when in its passive state before becoming active. Active mobile stations send measurements reports to the radio access network including inter alia its present at least one serving cell, quality of signal reception, and the like.
Mobile stations are pre-installed with a native Camping Cell Determination (CCD) mechanism for periodically determining a preferred camping cell from two or more available camping cells for receiving service in their passive state. Passive mobile stations automatically switch into their active states to upload registration area reporting events to their core network in the case of a change of their registration areas due to possible changes in their geographical location, their preferred camping cell, and the like. These registration area reporting events are important for assisting the core network to route services to mobile stations.
Cellular network operators are required to maintain very high grade of service and are constantly being challenged by a growing demand for more coverage areas, increasing traffic capacity, more and new services and better quality of service. Such needs require cellular network operators to constantly monitor the state and condition of the entire network and address a great variety of problems that affect different parts of the network and subscriber experience. Up to the present time, cellular network operators have three main information sources on which they can rely for detecting and diagnosing network operating problems such as load balancing, low quality of service, dropped calls, coverage holes, and the like. The information sources are as follows:
(a) Signal measurements reports transmitted by active mobile stations during their communication sessions. However, active mobile stations typically constitute no more than about 10% of a cellular network operator's entire subscriber base and therefore such information requires long periods of acquisition, and is statistical by nature.(b) So-called drive tests involving vehicles equipped with GPS and mobile stations and travelling along predetermined routes. Such information acquisition is time and resource consuming and does not supply cellular network operators with indicative real-time information about the state of their entire network and areas where subscribers might experience poor service.(c) Probes and Operation Support System (OSS) that monitor interfaces between network entities. In order to acquire such information, it is required to deploy probes on several interfaces, and to analyze their data. This approach relies on detecting anomalies in data traffic in order to detect and analyze the above problems.